1. Field of the Invention
The present invention relates to wireless tag readers and writers for reading information from wireless tags stuck to articles and for writing information to the wireless tags.
2. Description of the Related Art
As shown in FIG. 1, a wireless tag reader and writer 1 of this type is generally divided into multiple wireless-tag-read-and-write-storage compartments 2. The wireless-tag-read-and-write-storage compartments 2 have accommodated read and write boxes 5, as shown in FIG. 2 and to be specifically described later, for storing articles each having a wireless tag 3 at the end; e.g., mail 4. Since the wireless-tag-read-and-write-storage compartments 2 have a horizontal bottom, as described in Japanese Patent Publication No.2004-43049, the read and write boxes 5 have also been stored in each wireless -tag-read-and-write-storage compartments 2, with the bottom held in a horizontal state.
As shown in FIG. 2, when the conventional wireless tag reader and writer 1 stores multiple pieces of mail 4 each having a wireless tag 3 into the read and write box 5, parts of the mails with the wireless tag stacked thereon are overlapped and therefore the mail 4 is tilted because of the thickness of the stacked wireless tags 3 or the thickness of the contents of the mail 4. This poses the problem that the mail 4 slides toward this side, or toward an opening 6 through which the mail 4 is inserted, to come out of the normal readable and writable area 9 (hereinafter, referred to as a normal reaction area 9) of a read antenna 7 and a write antenna 8 fixed to part of the side wall, thus making it impossible to read positional information from the wireless tags 3 and to write management information to the wireless tags 3.
FIG. 2 illustrates the problem simply. In the drawing, upper two pieces of the mail 4 slide toward the opening 6 because of the thickness of the wireless tags 3 of the mail 4, to bring the wireless tags 3 out of the normal reaction area 9 of the read antenna 7 and the write antenna 8.